[The effect of hydrocortisone and insulin on the activity and isoenzymes of typrosine-alpha-ketoglutarate transaminase in the ctyostructures of the livers of rats of different ages].

Administration of hydrocortisone or insulin and also a simultaneous use of these hormones in a high dose caused a marked elevation of the total activity of tyrosine-alpha-ketoglutaric transaminase and its anode and cathode isoenzymes in the soluble fraction of the liver in the sexually immature (weighing 100-110 g) and mature (weighing 180-200 g) male rats. The stimulating effect of insulin was sharper in the young in comparison with adult animals. Administration of hydrocortisone caused a more pronounced elevation of the total tyrosine-alpha-ketoglutaric transaminase activity in the hepatic mitochondria of young rats than in adult animals. Insulin administration increased the activity of tyrosine-alpha-ketoglutaric transaminase in the mitochondria of the liver of the sexually mature male rats without significant changes of this enzyme in the sexually imature rats. A simultaneous injection of hydrocortisone and insulin to the sexaully mature male rats caused the same increase in the tyrosine-alpha-ketoglutaric transaminase activity in the hepatic mitochondria as after the administration of glucocorticosteriod alone. As to the sexaully immature males, the activity of the enzyme fell to the normal level. It is supposed that androgens played a significant role in the realization of the inducing action of glucocorticoids and insulin influencing the synthesis of tyrosine-alpha-ketoglutaric transaminase in different directions in the mitochondria of the liver of young and sexually mature animals.